Effect of Potassium Humate Application on Yield and Nutrient Uptake of Maize Grown In a Calcareous Soil

Potassium humate (K-humate) is a promising natural resource to improve yield and nutrient uptake by crops. A field experiment was conducted to assess the efficacy of Khumate application in combination with chemical fertilizers on enhancing yield and nutrient uptake of maize grown in a calcareous soil, western of Nile Delta, Egypt in two successive summer seasons (2015 and 2016). The Khumate was applied at a rate of 15 kg ha^-1 along with an increasing rate of chemical N, P and K fertilizers, varyingfrom 0 to 125% of the recommended dose. The results indicated that grain yield of maize significantly responded to application of K-humate. The results also indicated thatthe computed optimum grain yield of 7463 kg ha^-1 without application of K-humate can be obtained by applying 98% of the recommended dose of chemical fertilizers. However, in the presence of K-humate, the optimum yield of 8310 kg ha^-1 can be obtained by applying about 73% of the recommended dose of fertilizers. Nutrients uptake responded linearly to the increasing rates of chemical fertilizers, without or with K-humate application. However, the rate of increase in the presence of K-humate was substantially higher than that recorded at its absence. The difference in the increase of nutrients uptake was the highest for P, then N and K in the presence of K-humate. This study suggests that K-humate has the potential to increase crop yield, nutrient uptake and reduce the amounts of applied chemical fertilizers in calcareous soils.